Many electrophotographic machines, such as photocopiers or laser printers, use a detachable developer cylinder that contains a photosensitive member. The cylinder is also known as a cartridge or developer cartridge, and it is detachably mounted to the complete copier or printer. This construction enables users to maintain the printing capability of the device without the aid of a serviceman.
The developer cylinder is coupled to a drive mechanism that rotates the cartridge. U.S. Pat. No. 7,885,575 to Batori et al., which is incorporated by reference into this disclosure, describes an exemplary assembly for attaching the developer cylinder to the drive mechanism of the machine. As illustrated in the figures of Batori et al. and utilizing the reference numbers thereof, a drive shaft 100 of the main assembly side and a coupling member 156, which is a rotational force transmitting portion of the cartridge 2, connect with each other in interrelation with the mounting operation of the cartridge 2. By this, the drum 20 receives the rotational force from the main assembly 1 to rotate.
The drive shaft 100 is coupled with the drive transmitting means, such as a gear train and the motor provided in the main assembly 1. The free end portion 100a of the drive shaft 100 has a substantial semispherical shape and is provided with rotational force transmitting pins as the rotational force applying portion 100b.
The coupling member 156 has a rotational force receiving member 150, which includes a rotational force receiving portion 150e for receiving the rotational force at the free end portion thereof. In addition, the coupling member 156 has a spherical portion 160 mounted by penetrating the pin 155 through a rear end portion of the rotational force receiving member 150. The rotational force receiving member 150 is fabricated from a resin material, polyacetal, the polycarbonate, PPS, or the like. However, in order to enhance the rigidity of the rotational force receiving member 150, glass fibers, carbon fibers, and/or the like may be mixed in the resin material in response to the required torque load. The rigidity may further be enhanced by inserting a metal member material in the resin material, and the whole rotational force receiving member 150 may be made of metal or the like. The free end of the rotational force receiving member 150 is provided with a plurality of drive receiving projections 150d.
To facilitate coupling of the drive shaft 100 with the coupling member 156, the rigid coupling member 156 is pivoted about the pin 155 such that the rotational force receiving member 150 and the drive receiving projections 150d may be aligned with the drive shaft free end portion 100a and the force transmitting pins 100b. The pivot assembly (universal joint) may get stuck when installing a cartridge into the printer.
Moreover, U.S. Pat. No. 8,731,435 to Xu, which is incorporated by reference into this disclosure, discloses a complex control mechanism in an attempt to facilitate alignment between the drive shaft and the coupling member. As illustrated in the figures of Xu and utilizing the reference numbers thereof, the control mechanism 20 includes a control rod 15, which can rotate around a pivot on the cartridge casing, and an elastic means 14 mounted on the control rod. The control mechanism 20 is intended to control extension and retraction of the force receiving head 2 in the photosensitive drum driving assembly. While the control mechanism is intended to prevent the force receiving head from becoming stuck by a driving head 40 of the imaging device, the assembly is too complicated to reliably achieve the coupling function.
Further, U.S. Pat. No. 8,615,184 to Zhou et al., which is incorporated by reference into this disclosure, discloses a retractable shaft coupling in an attempt to facilitate alignment between the drive shaft and the coupling member. As illustrated in the figures of Zhou et al. and utilizing the reference numbers thereof, the driving component 1 includes a gear 2 having one fixed end and a longitudinal regulating component 11 having a rotational driving force receiver 3 outside the other end projecting from the gear 2. The longitudinal regulating component 11 can make a limited longitudinal and reciprocally translational movement along the longitudinal direction Z of the gear 2 relative to the gear 2 via the compressed force of the helical compression spring 8, the restoring force after losing the external force from the helical compression spring 8 and the longitudinal position limit from the position limit clevis pin 7. The longitudinal regulating component permits only axial displacements and does not permit angular misalignment and may get stuck when detaching a cartridge from the printer.
Accordingly, there is a need for a coupling and transmitting assembly that has a simple structure, facilitates installation and detaching of the cartridge, provides reliable transmission between the coupled components, and avoids the disadvantages of the known coupling and transmitting assemblies.